Cardiovascular diseases are a leading cause of death in the Western World. These diseases are multi- factorial, yet research reveals the pervasive role of mechanical factors. This proposal is a multidisciplinary research plan that aims to develop a nanoscale biosensing and imaging technology toward understanding cell-extracellular matrix interactions. Applied here to mechanobiology of vascular cells, the technology would be broadly applicable in the cell biology field. Many normal and pathophysiological vascular processes depend on cell responses to mechanical forces with integrins playing a central role. Current technologies have not permitted precise quantitative analysis of the mechanistic nature of integrin sensation of mechanical forces. Developments in biological applications of atomic force microscopy (AFM), particularly in combination with nanoscale optical biosensing technology, offer new opportunities for study of mechanobiology. Our strategy combines the spatial resolution and control capabilities of an AFM's nanoscale tip with the unique optical properties of nanoscale quantum dots to produce a Forster resonance energy transfer (FRET) bioprobe system. This system will determine the forces necessary to elicit cellular responses, detect cell mechanical responses and correlate them with integrin turnover at the cell membrane. Nanoscale semiconductor quantum dots present an excellent option in this FRET-based system. The specific aims are: 1. To develop a unique system consisting of optically active and biologically functionalized nano-probe for use in an integrated atomic force, multi-optical imaging system; and 2. To demonstrate the utility of this technology by investigation of the mechanobiology of the extracellular matrix- integrin-cytoskeletal axis in vascular smooth muscle cells through the development of the above nano-probe based system. The collaboration in this proposal is based on a strong existing partnership in the development and use of biosensing and imaging technologies at the nanoscale. Public Health Relevance: As cardiovascular disease is the leading cause of death, cardiovascular research is important nationally and internationally. We propose to develop a nanoscale biosensing and imaging technique that will be valuable for understanding cardiovascular disease. The development of the proposed nanoscale imaging and sensing device will also provide a flexible new tool for advancing our molecular understanding of the cell. [unreadable] [unreadable]